Electric furnace



Nov. 30, 1943.

R. G. LE TQURNEAU ELECTRIC FURNACE Filed Sept. 19 1942 5 Sheets-Sheet 1 INVENTOR RGleYburneau HTTYS Nov. 30, 1943. R. G. LE TOURNEAU 2,335,344

ELECTRIC FURNACE Filed Sept. 19, 1942 5 Sheets-Sheet 2 INVENTOR R6. LeYEurneau B 'Mmz:

Nov. 30, 1943. R. G. LE TOURNEAU ELECTRIC FURNACE Filed Sept. 19, 1942 5 Sheets-Sheet 3 lNVENTOR R. G. Le'ZbuI-n 8811,

HTTYS Patented Nov. 30, 1943 ELECTRIC FURNACE Robert G. Le Tourneau, Peoria, 111., assignor to R. G. Le Tourneau, Inc., Stockton, Calif., a corporation of California Application September 19, 1942, Serial No. 458,968

2 Claims.

This invention represents improvements in electric furnaces, and particularly electric arc furnaces which include electrodes projecting into a crucible from above to produce an are therein, th heat of which are melts the metal disposed in such crucible.

One of the objects of this invention is to provide an electric arc furnace which includes a crucible having a unique design and mounting; the crucible being generally spherical, pivotally supported, and cable actuated for tilting movement to and from a pouring position.

Another object of this invention is to embody novel mounts on an electric furnace to adjustably support the electrodes in guided relation on the crucible, and for movement therewith, whereby the crucible may be tilted and poured without necessity of first withdrawing the electrodes.

An additional object of the invention is to provide an electric arc furnace which includes a generally spherical crucible pivoted for tilting movement to and from a pouring position by means of a cable-control; there being electrodes adjustably supported by and movable with the crucible.

It is also an object of this invention to provide an electric furnace which includes a crucible, electrodes projecting into the crucible, said electrodes being separately mounted for adjusting movement relative to said crucible, and means to effect such movement; such means for each electrode being power actuated and selectively operable from a point remote from the crucible.

A further object of the invention is to provide an electric furnace which includes a tiltably mounted crucible having generally opposed pouring openings in the sides thereof; the crucible being adapted to tilt in one direction to pour slag out of one opening, and to tilt in the opposite direction to pour molten metal out of the other opening, whereby the slag and clean molten metal are discharged at separated points as is desirable.

A further object of the invention is to produce a simple and inexpensive device and yet one which will be exceedingly effective for the purpose for which it is designed.

These objects I accomplish by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings similar characters of reference indicate corresponding parts in the several views:

Figure 1 is a top plan view of the improved electric furnace.

Figure 2 is a sectional elevation on line 2-2 of Fig. 1.

Figure 3 is a sectional elevation on line 33 of Fig. 1, showing the crucible tilted to pour.

Figure 4 is a side elevation of the furnace in heating position.

Figure 5 is a fragmentary side elevation of one of the power actuated electrode mounts; the corresponding power unit being shown with the near side of its housing removed.

Referring now more particularly to the characters of reference on the drawings, the improved electric furnace comprises a substantially spherical, open-topped crucible made up of an outer metallic shell 1 provided with a fire resistant or refractory lining 2 of substantial thickness; the chamber of the crucible being indicated at 3, and said chamber being open at its upper end as at 3a. The crucible is normally disposed in an upright position, as shown in Figs. 1 and 4, and the lower portion of said crucible depends into a pit 4 extending below the floor F so that the crucible is accessible for loading, pouring, etc.

At the front the crucible is supported by a pair of rigid, transversely spaced legs 5 upstanding from the bottom of pit 4, the upper ends of legs 5 being pivoted as at 6 to projecting transversely spaced cars 1 fixed on the front of the crucible adjacent the horizontal center line thereof. The legs 5 are suitably braced, as at 8. Between the ears I and also adjacent the horizontal center line of the crucible the latter is formed with a pouring opening 9 having an outwardly projecting pouring lip I0.

Another pouring opening H, having an outwardly projecting pouring lip Ha, extends through the crucible in substantially the same horizontal plane as opening 9 and in generally opposed relation thereto, although the opening II is circumferentially offset somewhat relative to the rearmost point of the crucible in order to provide clearance for the tilt control mechanism, as hereinafter described. The openings 9 and H are blocked with suitable fire resistant material during the heating of the furnace and contents.

The tilt control mechanism for the crucible comprises a vertical post 12 mounted on the floor F in upstanding position adjacent butbeyond the rear end of the pit. A multiple reach block and tackle unit, indicated generally at I3, is secured with one sheave block I4 fixed in connection with the upper end of post i2. From said upper end of post l2 the block and tackle'um't extends downwardly at a slight forward slope; the lower sheave block [5 of said unit being disposed normally ad-- downwardly and away from the furnace to connection with a manually controlled power Winch (not shown).

At circumferentially spaced points on one side thereof, the crucible is fitted with three vertical slide beams 20, each beam including at its upper end a rigid arm ZI projecting inwardly over the crucible, and well insulated from said beams, as

indicated at Zia. These three arms 2| terminate at symmetrically spaced points above the opening 3a of the crucible. At their inner ends the arms 2! are each provided with an electrode clamp 22 which engages and supports a vertical, electrode 23; the electrodes depending from the clamps into chamber 3 of the crucible. This form of electrode clamp 22 is shown and described in detail in co-pending application for United States Lettersv Patent, Serial No. 458,966, filed September 19, 1942.

Each of the vertical slide beams is supported for up and, down adjustment by a lik .power actuated mount, and therefore a description of one such mount will suffice:

Each such mount comprises a pair of upstanding plates 24 which are secured to and project outwardly in parallel relation from the crucible mainly above the horizontal center line thereof, said plates being of substantial height. The corresponding slide beam is disposed between plates 24 and is guided therebetween by upper and lower rollers 25 engaging the outer face of beam 29, other rollers 26 engaging the inner face of said beam intermediate rollers 25, and additional upper and lower rollers 27 which engage the beam on opposite sides and at vertically spaced pointspall of the aforementioned rollers being mounted in connection with said plates 2d. As so guided, movement of the beam 28 is in a plane parallel to the vertical axis ofthe crucible whereby the electrodes 23 are moved in a corresponding plane.

Raising and lowering movement of each slide beam 29 is accomplished through the medium of the following power control unit, one of which isincluded in connection with each beam mount.

A housing 28 is fixed between plates 24' and encloses a cable drum 29, which is disposed with its axis at right angles to the direction of move ment of the corresponding slide beam 2% A cable 30 is wound about and at one end is anchored to drum 29. The other end of said cable extends downward out of housing 28 through a cable port 28a to a point adjacent the lower end of beam 20, whence it extends about a pulley 3i and leads back to a suitable anchor on one of the corresponding plates 2 A laterally disposed housing 33 mounted on and supported by housing 28 encloses a reversible electric motor 36 whose shaft 35 drives a train of reduction gears, indicated generally at 35, and which includes a worm and a driven gear assembly 36a which drives the shaft 37 on which the drum 29 is mounted. The motors 3 3 are selectively energized through the mediumof an electric cable 38 wh ch leads from each motor to a switch (not shown) remote from the crucible; these cables being suitably heat insulated.

Each of the housings 28 protects the corresponding drum 29, its cable 30, as well as the gear train 36, from damage which might otherwise result from splashing of molten metal from the crucible. In addition each housing 33 affords similar protection to the corresponding electric motor 3 2.

Electric current is supplied to the electrodes 23 through clamps 22 by bus bars 39 supported on arms 2! such bus bars extending in spaced relation over the corresponding slide beams 20 and therebeyond being connected with normally slack heavy-duty electric cables as. Each cable 49 loops downward from its bus bar 39 and thence extends upward and passes through an insulator 4| in a heat wall or shield 42 upstanding from the floor F between the furnace and an electric transformer 33 which is mounted on the floor, and to which transformer the cable iil connects.

In operation, the crucible is disposed in upright or non-tilted position for heating, as shown in Figs. 2 and 4; the proper vertical adjustment of the electrodes 23 being maintained automatically, as is customary in units of this type, by the flow or stoppage of the electric current in the electrode.

To pour the molten metal from the crucible the pouring openings 9 and II are cleared of blocking material, and then the furnace is tilted backward slightly by releasing cable reach I9 and extension of block and tackle unit l3. This results in the slag pouring through rear opening I l and over lip Ha into a suitable receptacle (not shown) disposed in the pit adjacent its rear end. After the slag has been thus discharged, a pull is applied to the cable 59, shortening the block and tackle unit to a substantial extent and causing the crucible to swing upwardly and forwardly about pivots 6; a substantial tilt being possible due to the use of the cradle arrangement of cables ii. The molten metal then pours through the front opening 9 over lip I0 and falls downward into a pouring ladle or the like (not shown) which has previously been set in the pit 4 in proper receiving position. The pouring opera-, tion can be nicely controlled by means of the poweractuated block and tackle unit l3, and due to the factthat the mounts for the electrodes are supported wholly on the crucible, the latter may be tilted for pouring regardless of the position of said electrodes.

From the foregoing description it will be readily seen that I have produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred, construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims. i I

Having thus described my invention, what I claim as new'and useful anddesire to secure by Letters Patent is: V v I 1. In an electric furnace which includes a tiltably mounted crucible having a top opening, an electrode projecting longitudinally into the crucible from above, and a mount for said electrode secured on and movable with the crucible, said mount comprising a pair of up-. standing parallel plates secured in spaced relat1on to and projecting outwardlyfrom the crucible, an upstanding slide beam disposed between said plates, guide means mounted in connection with the plates engaging the slide beam in guiding relation, a housing secured between said plates outwardly of the beam, 9. cable drum mounted in and enclosed by said housing, the latter having a cable port in the bottom thereof, a cable depending from said drum through the port, a sheave journaled on the lower end' of the slide beam, the depending cable extending about the pulley and thence passing upward to a fixed connection with the crucible some distance above said pulley, and power means arranged in driving relation to said cable drum.

2. In an electric furnace which includes a tiltably mounted crucible having a top open, an electrode projecting longitudinally into the crucible from above, and a mount for said electrode secured on and movable with the crucible, said mount comprising a pair of upstanding parallel plates secured in spaced relation to and projecting outwardly from the crucible, an upstanding slide beam disposed between said plates, guide means mounted in connection with the plates engaging the slide beam in guiding relation, a housing secured between said plates outwardly of the beam, a cable drum mounted in and enclosed by said housing, the latter having a cable port in the bottom thereof, a cable depending from said drum through the port, a sheave journaled on the lower end of the slide beam, the depending cable extending about the pulley and thence passing upward to a fixed connection with the crucible some distance above said pulley, and power means arranged in driving relation to said cable drum; said power means including a gear train disposed in the housing in driving relation to said drum, an electric motor mounted to one side of the housing and connected in driving relation to said gear train, and another housing surrounding said electric 20 motor.

ROBERT G. LE TOURNEAU. 

